Property, Plant and Equipment alt (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property, Plant and Equipment [Line Items]
Impairment of long lived assets		$ 35.8
Leasehold Improvements, Gross	63.5	23.2
Depreciation	480.0	224.6	207.7
Liftboats [Member]
Property, Plant and Equipment [Line Items]
Impairment of long lived assets		$ 46.1	$ 32.0